This invention relates to a comminutor-pump assembly of a type suitable for use, for example, in a system for the application of livestock waste to land by irrigation. These systems are becoming increasingly popular because of the low cost and the ease of use thereof as compared with other systems. However, irrigation systems of this type require reliable means for reducing the size of the solids so as to avoid clogging of the centrifugal pump and the openings in the sprinkler heads or large guns used to spray the sewage and other solids out onto the field. It is also essential to maintain sufficient pumping pressure in the system.
The comminutor-pump assembly of the invention is constructed and arranged to achieve reliable comminution and to maintain a high pumping pressure. To these ends, the comminutor-pump assembly of the invention is constructed so that the comminutor and the pump are driven by the same prime mover, the pump being arranged to draw the sewage into a comminution chamber containing a rotating hollow cylinder which functions as a combination cutter and strainer. The solids in the sewage are comminuted to a size small enough to pass through openings in the rotating cylinder into the interior thereof from which the comminuted particles are pumped to the irrigation spraying location by the pump. The pump shaft has a drive shaft extension which extends through the center of the rotating cylinder to drive a planetary gear system arranged so that the rotating cylinder is driven at a speed much less than the pump speed.
Another feature of the invention is the provision of large cutting teeth, each of which is provided with a plurality of smaller teeth to utilize a grinding action in the comminution of the solids. Also, the teeth are distributed around the exterior of the comminutor drum to cooperate with cutting blades in the comminution chamber so as to maintain a relatively steady cutting action to thereby avoid intermittent surges in power requirements.